From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933410AbcDFIGW (ORCPT ); Wed, 6 Apr 2016 04:06:22 -0400 Received: from mail.skyhub.de ([78.46.96.112]:39223 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752731AbcDFIFW (ORCPT ); Wed, 6 Apr 2016 04:05:22 -0400 From: Borislav Petkov To: X86 ML Cc: LKML , "H. Peter Anvin" , Ingo Molnar , linux-edac , Thomas Gleixner , Tony Luck Subject: [PATCH 2/3] x86/mce: Remove explicit smp_rmb() when starting CPUs sync Date: Wed, 6 Apr 2016 10:05:15 +0200 Message-Id: <1459929916-12852-3-git-send-email-bp@alien8.de> X-Mailer: git-send-email 2.7.3 In-Reply-To: <1459929916-12852-1-git-send-email-bp@alien8.de> References: <1459929916-12852-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Davidlohr Bueso mce_start() has an explicit smp_wmb() to serialize writes to global_nwo and mce_callin. However, atomic_inc_return() implies barriers on both sides of the call, as such simply rely on this full SMP barrier. Signed-off-by: Davidlohr Bueso Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Thomas Gleixner Cc: Tony Luck Cc: x86-ml Link: http://lkml.kernel.org/r/1458602396-840-1-git-send-email-dave@stgolabs.net Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/mcheck/mce.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index f0c921b03e42..6b7039c166b8 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -830,9 +830,9 @@ static int mce_start(int *no_way_out) atomic_add(*no_way_out, &global_nwo); /* - * global_nwo should be updated before mce_callin + * Rely on the implied barrier below, such that global_nwo + * is updated before mce_callin. */ - smp_wmb(); order = atomic_inc_return(&mce_callin); /* -- 2.7.3